FIG. 11 is a perspective exterior view of a prior art card reader. Referring to FIG. 11, an antenna unit 101 for transmitting and receiving signals, a power supply circuit 102, and a control circuit 103 are enclosed within a main body 100.
When a card 110 (enclosing an antenna unit and an integrated circuit element inside) is brought in close proximity to the main body 100, in a direction of an arrow 120, signals are exchanged by means of a magnetic field between the antenna unit 101 enclosed in the main body 100 and the antenna unit enclosed in the card 110, so as to convert or erase data within a memory in the integrated circuit element ("IC"), or to store data from the main body 100 into the IC inside of the card 110.
Card readers of the type described above are utilized as input/output devices of systems that deal with commuting passes, prepaid cards, etc., since the data in a card 110 can be rewritten by simply bringing the card 110 in near proximity to the main body 100.
Also, another prior art card reader is provided with a card transfer path, through which a card is transferred by transfer rollers, etc. to a predetermined position, and signals are exchanged at the position between an antenna unit inside the card reader and an antenna unit in the card.
While the above prior art structure is convenient because it carries out communication between the card 110 and the main body 100 by simply bringing the card 110 near to the main body 100, it is also inconvenient, on the other hand, since the card 110 does not provide a visible display of data that are stored in the card, for example, the balance of money left for the card in the case of a system for processing a prepaid card.
Although a card reader of the type having a card transfer path can store information for visible display, they are not suitable for application in a system for handling commuting passes (including passenger tickets), etc., because they take time to transfer the cards and are slow to process the cards when used for the sole purpose of exchanging data between the cards and the card readers.